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2020-01-23

FAQ 004318 | Is it possible to connect a rib member to two surfaces with different thicknesses?

Question:
Is it possible to connect a rib member to two surfaces with different thicknesses? And where can I check the cross-section properties of this composite cross-section? In RFEM, I can only see the eccentric rectangular cross-section and its cross-section properties.

Answer:
You can connect a rib member to a line on two surfaces with different thicknesses.

To determine the stiffness or internal forces, the eccentricity of the rectangular cross-section is determined using the mean value of both connected surfaces in RFEM.

For design in RF‑CONCRETE Members, the add-on module determines a special cross-section, which is displayed in Window "1.4 Ribs" of the add-on module.

By clicking the "i" button (see Image 02), it is possible to open an info dialog box for the generated rib cross-section, where you can see all cross-section properties applied for the design in the add-on module, such as the position of the shear center and center of gravity, and so on.

When adjusting the "effective width" in Window "1.4 Ribs" (for example, to 0.50 m), this has an impact on the cross-section applied in RF‑CONCRETE Members and the cross-section properties of it.

However, this does not affect the stiffness or the determination of internal forces in the 3D model in RFEM.